Neurobiologists at the Friedrich Miescher Institute for Biomedical Research (including new NERF principal investigator Karl Farrow) have identified switch cells in the retina that facilitate our ability to see both in the dark and in the light. The cellular switch activates distinct neuronal circuits at a defined light level. In this way, computations suited specifically for vision in low and high light levels are switched on or off. This facilitates the transition from night to day vision. The scientists have published their results in Neuron.
Farrow K, Teixeira M, Szikra T, Viney TJ, Balint K, Yonehara K, Roska B (2013) Ambient illumination toggles a neuronal circuit switch in the retina and visual perception at cone threshold. Neuron. 2013 Mar 26. doi:pii: S0896-6273(13)00172-4. 10.1016